The part of the program above show you again with 2 methods in line 25 and 36 which do call the same method. That method is belonging to class “javax.crypto.spec.SecretKeySpec” which did to import from line 8 of the program. Let me remind you again that the former method use for encryption and the later use for decryption. The decryption uses the same key of encryption for decrypt. So, the 2 parameters on both methods always use the same parameter’s values.